Fan Control Device with High Frequency PWM Support and Hardware Monitoring Features
Datasheet
3.3V
12V
Fan
470
M
PWMx
MMBT2222
Figure B.2 Fan Drive Circuitry (Apply to PWM Driving One Fan)
3.3V
10k
Tach
TACH
Input
Output
from Fan
D1
IN4148
Note: For fans controlled directly by a PWM, it is suggested to implement
the optional diode (D1) to protect the tachometer input from large voltage
spikes generated by the fan.
Figure B.3 Fan Tachometer Circuitry (Apply to Each Fan)
Revision 0.4 (04-04-05)
SMSC EMC6D103
DATA8S8HEET